Treatment of crude oils

ABSTRACT

A process and apparatus to extract and recover heavy metals and sulfur from crude oil or petroleum fuel products including the steps of emulsifying the crude oil with an emulsifying agent, adding a leach solution to the emulsified crude oil and leaching the emulsified crude oil at elevated temperature and pressure to give a leached emulsified crude oil. The leach solution may be acid or alkali. A proportion of the leach solution is extracted for recovering heavy metals. There can also be a microwave hydro-treating step using hydrogen gas at a temperature below 220° C. to ensure there is no quality degradation in the crude feed to produce a desulfurized crude oil and a hydrogen sulphide by-product and recovering sulfur from the hydrogen sulphide by-product.

FIELD OF INVENTION

This invention relates to the treatment of crude oils or petroleumproducts to extract heavy metals and sulfur resulting in a crude oils orpetroleum products which is readily refined in conventional oilrefineries or resulting in the crude oils or petroleum products able tobe used in industry and transportation without causing environmentaldamage.

PRIOR ART

Studies have been made about the distribution and possible structure ofheavy metals in petroleum products such as “Mechanism of Occurrence ofMetals in Petroleum Distillates” R. A. Woodle and W. B. Chandler, Jr,Industrial and Engineering Chemistry, v.44, No.11, Nov. 1952, p. 2591.More recently, Energy BioSystems Corporation of Woodlands, Tex., USA(“Recent Advances in Biodesulfurization of Diesel Fuel” 1999 AnnualGeneral Meeting, National Petrochemical and Refiners Association, Mar.21–23, 1999, San Antonio, Tex., USA) have claimed success in removingsulfur from petroleum products by biodesulfurisation using a microbe.This process deals only with sulfur and the microbes have problems withremoving some type of sulfur compounds such as 4,6 dimethyldibenzothiopene; further, there is a by-product hydrocarbon compoundwhich Energy BioSystems believe can be used as a surfactant basematerial. BioSystems suggest that their process would combine well withconventional hydro-desulfurisation in removing sulfur from petroleumproducts by pre-conditioning the petroleum product with theirbiodesulfurisation.

The conventional commercial method to remove sulfur usually from theresidual of a distillation column is known as hydro-desulfurization.This is usually carried out at a high temperature of about 427 C withhydrogen gas applied to the charge. Catalyst such as cobalt andmolybdenum on alumina are used to enhance the reaction.

Conventional hydro-desulfurization can not be applied to crude oilbecause the high temperature required will shift the TBP curve to thelight end and produce low value gas and petroleum products. For similarreason, hydro-desulfurization of petroleum products such as automotivediesel would affect the desired quality of the petroleum product.

Kirkbride, C. G. was granted U.S. Pat. No. 4,234,402 (Nov. 18, 1980) forremoving sulfur from coal and crude petroleum by applying microwaves topetroleum crude oils at room temperature but 1000 psig pressure ofhydrogen. On a petroleum fraction obtained between the boiling pointrange of 400 to 500 degrees Fahrenheit containing 0.1% sulfur, Kirkbrideobtained a sulfur removal of 86% by applying 1000 megacycles ofmicrowave for 40 seconds. Applying microwaves under the same conditionsbut for 60 seconds on a crude sample containing 7% sulfur, Kirkbride wasable to remove about 93% of the sulfur. Kirkbride preferred a batchsystem for his process which is a major disadvantage as continuous largecapacity through-put processes are required by the oil industry. This isprobably the main reason why Kirkbride's process was not adopted by theoil industry in spite of Kirkbride's subsequent U.S. Pat. No. 4,279,722dealing with the use of microwaves in petroleum refining. Kirkbride'suse of low temperature is a disadvantage as the applicants experimentalobservations indicate that microwaves are more efficient at highertemperatures. This is important where the crude oil sample containssulfur compounds which are difficult to remove.

Nadkami et al were granted U.S. Pat. No. 4,408,999 (Oct. 11, 1983)concerning beneficiation of coal, oil shale, and similar carbonaceoussolids to remove inorganic constituents by subjecting the carbonaceoussolids with microwaves in the presence of an aqueous acid solution.Nadkami's process probably was not adopted to commercial practicebecause it is more economical to recover the sulfur from the flue gasand the heavy metals from the ashes after the coal is burnt in a boileror furnace, in spite of corrosion problems in tubes and refractories.

There has not been a U.S. patents granted on this subject until May,2000 probably because of the lack of development in large industrialsize microwave generators and the means to introduce large quantities ofthe microwave into the commercial size reaction vessels.

U.S. Pat. No. 6,068,737 (May 30, 2000) was granted to De Chamorro, et alfor the simultaneous removal of metals and sulfur from carbonaceousmaterial using an acid medium and subjecting the mixture to microwaveenergy. This patent is very similar to Nadkami et al U.S. Pat. No.4,408,999 on a process for removing sulfur and heavy metals contained ininorganic material from solid carbonaceous material. De Chamorro et alconducted their tests only on fine granules of coke and then claimed theprocess applicable to a wide range of carbonaceous material includingbituminous sand and crude oil. This type of leaching of fine solidparticles is similar to Applicant's U.S. Pat. No. 5,393,320 (Feb. 28,1995) on the leaching of fine particles of nickel laterite ore with acidwhile the mixture is being irradiated with microwave energy. Chamorro etal did not describe the technique of efficiently contacting the crudeoil and the acid leachate as this is very important for the successfulleaching reactions between the acid medium, the sulfur and metalliccompounds, and the microwaves. It must be appreciated that the claims ofDe Chamorro et al on crude oil are of a general nature and do notprovide details of equipment or techniques which will make the process apractical reality. There were no details of the procedure for recoveringthe heavy metals and sulfur from the leach liquor. Further, withoutgiving any basis, Chamorro et al state that their process applies onlyto crude oil with an API Index which exceeds 6 degrees. Applicant havein their laboratory a heavy crude with an API of 8 degrees. Thismaterial is so viscous that a quarter inch indentation at 18 C ambienttakes about 1 hour to reform. An oil or bitumen of 6 degrees API wouldbe more viscous and the leaching process described in general by DeCamorro would not function in removing sulfur or heavy metals even atthe temperature of the boiling point of the acid solution and 200 psigpressure specified by De Chamorro et al. To leach sulfur and heavymetals satisfactorily, the leach solution must be in contact with thesulfur and heavy metal molecules and the conventional heat or microwavesat the required time. This contact exposure requires intimate contactbetween the leach solution and the crude oil. The intimate contactrequires a very large contact surface. This is achieved by breaking upthe crude oil into very fine particles in the mixture of crude oil-leachsolution.

Heavy crude oils which normally contain high sulfur and heavy metals areusually very viscous. Hence it will be seen that the first requirementof the process is to make this crude oil more fluid and broken-up intofine particles as the crude oil is mixed with the leaching solution toallow the greatest contact between the metallic compounds and sulfurcompounds in the crude oil and the leaching solution. After leaching,the leached crude has to be separated from the leachate and theremaining small amount of leach solution need to be removed from theleached crude by washing to make the leached crude suitable forrefining. This was not appreciated by De Chamorro et al as they reportedonly experimental results on leaching very fine granules of coke. Inthis invention, breaking up the crude oil is accomplished by applyingcommercially available solvents and emulsifiers, and the use of anapparatus which can break-up the crude oil into very fine particles andapply conventional heat and/or microwaves at the same time. After theleaching is accomplished, the leached crude oil and the loaded leachsolution are separated.

The leaching step is preferably carried out at the lowest possibletemperature to avoid degrading the quality of the crude oil. Laboratorytests also indicated that high pressure during leaching is desirable forefficient extraction. For some crude oils, conventional heating and acidelectro-leaching may be sufficient. Some crude oils may be treatedsatisfactorily by conventional heating, acid electro-leaching andirradiation with microwave energy.

In this invention, if sufficient sulfur is not removed during acidleaching, the crude oil may be subsequently leached with an alkali suchas caustic soda or soda ash with microwave energy, or hydro-desulfurizedusing microwave energy and hydrogen gas. The use of microwaves inremoving sulfur from crude oil at comparatively lower temperature issupported by the concept that hydrocarbon molecules are more transparentto microwaves than organo-sulfur or organo-sulfur-metallic compounds.Microwave energy would activate the organo-sulfur andorgano-sulfur-metallic compounds preferentially. The temperature ofmicrowave hydro-treating is substantially less than conventionalhydro-treating, minimising the effect on the quality of the crude oil.

Microwave generating equipment has advanced considerably in the pastdecades but industrial microwave equipment still has a high capital costand higher unit energy cost than conventional heat. None of the U.S.patents disclosed above mention carrying out comparative tests usingonly conventional heat without microwaves. Applicant's extensiveexperience in the leaching of minerals indicate that some minerals areleached satisfactorily by conventional heating only but other mineralscompounds are only leached satisfactorily using conventional heat andmicrowaves. Conventional heating must be considered as a first option totreat a crude oil to meet desired specifications if the treatment is toresult in the lowest capital and operating cost.

The prior art shows the principles of leaching, electromagneticradiation, and hydro-desulfurization in processing carbonaceousmaterials are well known. The challenge is to apply these principlesusing innovative and novel techniques and apparatuses to remove sulfurand heavy metals from a wide range of crude oil and petroleum productsin a commercial process.

DESCRIPTION OF THE INVENTION

Before describing the present invention, it must be recognised thatevery crude oil has its own characteristics and variation in the formand quantity of sulfur and heavy metals. The metals and sulfur couldoccur as fine discrete particles mixed with the crude oil such as ironpyrites or gypsum or a wide range of organo-sulfur ororgano-sulfur-metallic compounds in various configurations such asparaffinic or cyclic molecular formation. The process and apparatus ofthe present invention is capable of treating this very wide range ofcrude oil feedstock and petroleum products to produce the acceptablequality of the products at a viable capital and operating cost.By-product or waste disposable must be considered as one waste productsuch as calcium or sodium salt may be acceptable in one plant locationbut not in another plant location.

In one form therefore the invention is said to reside in a process andapparatus to extract and recover sulfur and heavy metals from crude oilor petroleum fuel products consisting of the steps of emulsifying thecrude oil with an emulsifying agent, adding a leach solution to theemulsified crude oil and leaching the emulsified crude oil at elevatedtemperature and pressure in an appropriate leaching vessel or vessels togive a leached emulsified crude oil and a leachate, separating theleached emulsified crude oil and the leachate, removing a proportion ofthe leachate and recovering sulfur heavy metals therefrom, washing theleached emulsified crude oil with water and separating the leachedemulsified crude oil and the washing water.

Preferably the process further includes the step of microwavehydro-desulfurizing the leached and washed crude oil using hydrogen gasat a temperature below 220 degrees Celsius to ensure there is no qualitydegradation in the crude feed to produce a desulfurised crude oil and ahydrogen sulphide by product; and recovering sulfur from the hydrogensulphide by product using a commercial process.

This more expensive microwave hydro-desulfurization with the accessoryplants is generally applied where the sulfur content of the crude oil orpetroleum product is very high and there is a very large quantity of thecrude oil to be treated. Aside from removing sulfur from compounds suchas mercaptans, sulphides, disulphides and thiopenes, microwavehydro-desulfurization will also improve the product crude quality bydenitrogenation of pyrroles and pyridines, deoxidation of phenols andperoxides, dehalogenation of chlorides, hydrogenation of pentenes topentanes, and some hydrocracking of long chain hydrocarbon molecules.

Where the quantity of the acid leached crude oil or petroleum product isrelatively small and the amount of sulfur to be further removed is alsorelatively small, the acid leached and washed crude oil may be subjectedto an alkali leach with microwaves and then washed to meet final sulfurspecifications. The sulfur is recovered in the waste product as sodiumsulphate.

In a preferred embodiment of the invention the leaching step maycomprise the steps of leaching the emulsified crude oil with an acidleach solution while microwave energy is applied, washing the acidleached emulsified crude oil with water, separating the crude oil fromthe wash water, re-emulsifying the crude oil as required, leaching there-emulsified crude oil with an alkali leach solution while microwaveenergy is being applied, washing the alkali leached re-emulsified crudeoil with water, and separating the crude oil from the wash water. Theacid and alkali leached crude oil may subsequently be subjected tomicrowave hydro-desulfurization if required to meet productspecifications.

The viscosity of the feedstock crude oil may be reduced at the beginningof the process by the addition of a solvent before emulsification andthe solvent may be recovered for reuse by distillation before theprocess of this invention. Up to 20% by volume of a solvent may be addedto the crude oil before emulsification depending on the viscosityproperties of the crude oil and the solvent.

One class or more of emulsifying agents for leaching may be added at anamount of up to 0.5% by weight of the crude oil. The emulsifying agentshould be sufficiently stable in acid or alkali conditions andtemperature of below 160 C.

The emulsifying agents are selected so that the least amount is requiredto achieved emulsification and any left-over after leaching does notreduce the quality of the crude oil or petroleum product.

The leach solution may be a solution of an inorganic acid or alkaliwhich is used in an amount of about 5 percent to 50 percent by volume ofthe crude oil.

The leaching process may be carried out in a vertical cylinder or amulti-compartment horizontal vessel capable of containing the pressure,temperature, and corrosive nature of the crude oil-leaching solutionmixture.

The leaching may be carried out in a vessel provided with a stand pipeand an agitation mechanism consisting of an impeller and baffle assemblysufficient to circulate the mixture of crude oil-leach solution andprovide intense agitation and mixing in the area where microwave energyis being applied. The washing vessels may be fitted with the sameagitation mechanism but without microwave supply and operate at ambientpressure.

The leaching vessel may be provided with external insulation andinternal or external means of conventional heating.

The leaching vessel may be provided with a means of applying largequantities of microwave energy at the space of intense mixing of thecrude oil and the leach solution.

The leaching stage may be carried out at temperatures of between 25 C to160 C and pressure of up to 100 bars.

Heating at the leaching step may be carried out by the application ofconventional heating only, the application of microwave energy or acombination of conventional heating and microwave energy.

The leaching step may consist of one or more stages with a liquid liquidseparation between stages and the leaching may be arranged incountercurrent mode.

There may be one or more stages of liquid liquid separation between theleaching step and the washing step.

The washing step may consist of one or more stages with a liquid liquidseparation between stages and the washing step may be arranged incountercurrent mode.

There may be one or more stage of liquid liquid separation between thewashing step and the hydro-desulfurization step.

The wash water may contain a small amount of alkali to ensure that theacid leached and washed crude oil has the best quality for thesubsequent microwave hydro-desulfurization step.

The microwave energy may be applied to the leach solution at 800 to22,000 megahertz frequency.

The leach solution may contain an inorganic acid or alkali, or include asmall amount of oxidising agent such as hydrogen peroxide.

The leaching step may include anode cells in the leachate circuit tooxidise suitable ions such as ferrous and vanadium ions before theleachate is recycled to the leaching step. Aside from the acid, theferric and vanadic ions produced from leached ferrous and vanadous ionsat the anode will participate and assist in the leaching process.

The step of the recovering heavy metals may include the steps ofseparating a bleed solution from the main leaching stream after theanode cell, adjusting the pH of the bleed solution to about between 1.5and 2.5 using calcium or sodium hydroxide or carbonate, applyinghydrogen sulphide gas to the hot solution to precipitate base metals andother metals susceptible to this treatment and filtering theprecipitate, adjusting the pH of the boiling solution to a pH of aboutbetween 3.0 to 3.5 using soda ash to precipitate compact iron oxidewhich is filtered from the solution, applying a small amount of anoxidising agent such as hydrogen peroxide to convert vanadium ions totheir highest oxidation state before applying soda ash or ammonia to thesolution to increase the pH to about 3.6 to 4.6, applying hydrogensulphide gas to the solution to precipitate vanadium sulphide, filteringthe vanadium sulphide precipitate, adjusting the pH of the hot solutionto between 8 and 10 using soda ash or ammonia to precipitate vanadiumhydroxide and subjecting the waste solution to a vacuum to recover anyhydrogen sulphide gas left in the waste solution before the solution isdiscarded.

The acid leached and washed crude oil may further be treated withmicrowave hydro-desulfurisation or alkali leaching.

Conventional heating is used to raise the temperature of the crude oilbetween the washing step and the hydro-desulfurization step.

The microwave hydro-desulfurization crude oil product containing thewaste product of hydrogen sulphide mixed with un-reacted hydrogen gas iscooled and the hydrogen and hydrogen sulphide gas are stripped from thecrude oil. Hydrogen is separated and re-cycled to the microwavehydro-desulfurization while the hydrogen sulphide gas is fed to aconventional Claus or Stretford process to convert the hydrogen sulphideinto elemental sulfur and hydrogen gas which is re-cycled to themicrowave hydro-desulfurization process.

The microwave hydro-desulfurization may be carried out at temperature ofup to 220 C and pressure of up to 100 bars unless higher temperature andpressure are required for increased hydro-cracking for a particularcrude oil or petroleum product.

The microwave hydro-desulfurization process may be carried out in thepresence of catalyst selected from cobalt and molybdenum on alumina toenhance the efficiency of the reaction or to reduce the requiredhydro-desulfurization temperature and pressure.

The microwave hydro-desulfurization may be carried out in a vesselcomprising a vertical cylindrical vessel or a multi-compartmenthorizontal cylindrical vessel fitted with a standpipe and a hollow shaftfor the admission of hydrogen and an impeller-baffle assembly tointensely and intimately mix the leached crude and the hydrogen gas atthe space where the microwave energy is applied.

The microwave hydro-desulfurization vessel may be provided with externalinsulation and internal or external source of conventional heating.

The microwave energy applied to the microwave hydro-desulfurizationvessel may range between 880 and 22,000 megahertz where the mostefficient frequency is determined experimentally for each crude oilsample.

The microwave hydro-desulfurization vessel may be fitted with microwavegenerators and wave guides through quartz windows at the bottom or sidesof the microwave hydro-desulfurization vessel. Alternatively themicrowave energy for the hydro-desulfurization step is applied in aseries of pipes where the crude oil is being circulated from a holdingvessel. In a further arrangement the microwave energy for thehydro-desulfurization step may applied to the crude oil through waveguides inside the vessel and wherein the microwave energy is deliveredto the crude oil through slots in the wave guide. Alternatively themicrowave energy for the hydro-desulfurization may be delivered at theend of several short wave guides inside the vessel under convectiontubes at a space where there is maximum intense and intimate mixing ofthe crude oil and hydrogen gas. The microwave energy for thehydro-desulfurization may be delivered at the end of antennae inside thevessel under convection tubes at a space where there maximum intense andintimate mixing of the crude oil and hydrogen gas.

BRIEF DESCRIPTION OF THE DRAWINGS

This then generally describes the invention but to assist withunderstanding reference will now be made to preferred embodiments asillustrated in the accompanying drawings.

FIG. 1 shows a flow sheet of a crude oil treatment process according toone embodiment of the present invention applying hydro-desulfurizationafter the acid leach.

FIG. 2 shows a flow sheet of a crude oil treatment process according toan alternative embodiment of the present invention applying acidleaching and alkali leaching.

FIG. 3 shows a more detailed diagram of a process according to analternative embodiment of the present invention of the acid leachingfollowed by hydro-desulfurization of a crude oil or petroleum product.

FIG. 4 shows a more detailed diagram of a process according to analternative embodiment of the present invention of acid andelectro-leaching followed by alkali leaching of a crude oil or petroleumproduct.

FIG. 5 shows a diagram of a process according to an alternativeembodiment of the present invention of the acid leaching andelectro-leaching followed by hydro-desulfurization of a crude oil orpetroleum product.

FIG. 6 shows a diagram of a process according to the present inventionof acid leaching followed by alkali leaching and using solventextraction for the recovery of metals from a refinery feedstock.

FIG. 7A shows one embodiment of a leach vessel suitable for the presentinvention.

FIG. 7B shows an alternative embodiment of a leach vessel suitable forthe present invention.

FIG. 8A shows one embodiment of a reaction vessel suitable for thepresent invention.

FIG. 8B shows an alternative embodiment of a reaction vessel suitablefor the present invention.

FIG. 8C shows a further embodiment of a reaction vessel suitable for thepresent invention.

DISCUSSION OF PREFERRED EMBODIMENTS

FIG. 1 shows a flow chart for the preferred sequence of removing heavymetals and sulfur from a heavy sour crude oil. The microwave assistedleaching process for the crude oil will make the crude oil moresusceptible for the low temperature microwave hydro-desulfurization toremove more sulfur. The process is best carried out at the oil fieldwhere the sour crude is produced because piping the viscous sour crudeis difficult and the sour crude causes severe corrosion on a pipeline.

Heavy sour crude from well 15 is usually very viscous and it may benecessary to add a solvent or a cutting agent in mixer 1 to make thecrude oil sufficiently fluid to pipe it to a central sulfur and heavymetals processing plant. The solvent may be injected into the well ormixed at the surface. The large amount of solvent can be reduced bydistillation 2 by heating the crude oil after it has been transferred inpipeline 3 to the processing site. Recovered solvent is recycled to themixer or to the well.

The crude oil is then emulsified by mixing in a mixer 4 with emulsifyingagents 5 and water 6.

Water based leaching solution 14 is added in the leaching step. Themicrowave leaching apparatus 7 must be capable of high pressure andresist the corrosive mixture of the crude and leach solution. A crudeoil whether it is easy or difficult to leach will contain sulfur andmetallic compounds that are easy to leach and compounds which aredifficult to leach. A proportion of the leach solution is extracted andchemicals added 17 as will be discussed later for extraction of metalsand sulfur compounds 16.

After leaching and washing the crude oil is transferred to a microwavehydro-desulfurizing stage 9. Hydrogen is added at 10 and after treatmentas will be discussed in more detail later, the desulfurized oil iscooled before hydrogen sulphide and excess hydrogen is removed instripper 12. Hydrogen and hydrogen sulphide are separated and thehydrogen sulphide is treated at stage 11 to give elemental sulfur 18.Hydrogen is recycled to the hydrogen supply 10 to the desulfurisationstep.

The cleaned crude oil 19 and any light fraction separated in thestripper are remixed to form the final clean oil product 20.

FIG. 2 shows an embodiment of this process where the microwavehydro-desulfurization is replaced by alkali leaching of the sulfur leftafter acid leaching. The process is the same as in FIG. 1 until afterthe washing stage. The acid leached and washed crude oil is changed intomixer 22 where emulsifying agents 21 and water 23 are added. Causticsoda or soda ash 24 is added for the alkali leaching process 25 usingeither or both conventional heat and microwave energy. After liquidliquid separation and washing the leach solution and wash water 26 areevaporated 27 to separate the excess caustic soda 30 and the sodiumsulfur salts 28. The clean oil 29 is delivered to the storage orpipeline.

FIG. 3 shows an embodiment of this invention consisting of acid leachingand microwave hydro-desulfurization and the recovery of the metals.Crude oil or petroleum product 31 is delivered to mixer 34 whereemulsifiers 33 and water 32 are added. The mixing along with recycledleachate 42 is delivered to first leach vessel 35 which appliesconventional heating and pressure to the mixture. After leaching, liquidliquid separation of the mixture is carried out using a device such as aliquid vortex separator 36 where the partially leached crude oil isdischarged into a second acid leaching stage and the leachate 37 isdelivered to the next leach stage where the leaching vessel 40 isprovided with a microwave energy generator. Acid make-up 38 and anoxidising agent 39 such as hydrogen peroxide are added to leach vessel40. To ensure maximum removal of the leachate, the product mixture fromleach vessel 40 is subjected to two or more liquid liquid separationstages where the leachate 42 is recycled to leach vessel 35 and the acidleached crude oil 44 is delivered to the washing section mirror 45 withthe wash liquor 52 from the second stage wash 51. The mixture from mixer45 is passed through a liquid liquid separator 46 where the partiallywashed crude oil is delivered to mixer 48 and the wash liquor 50 isdelivered to the weak acid water storage to be used in making acidsolutions in the leaching stage. Wash water 47 which may contain somealkali is added to mixer 48. The mixture from mixer 48 is passed throughtwo or more liquid liquid separation units 49 and 51 to ensure maximumremoval of wash water with the first wash water 52 delivered to thefirst wash mixer 45. The leached and washed crude oil 53 is passed tothe heat exchanger 54 and then to the heater 55 before processing in themicrowave hydro-desulfurization vessel 56 where hydrogen 57 andmicrowave energy 58 is applied. The hydro-desulfurized oil 59 isdelivered to a hydrogen sulphide stripping section (not shown).

For metals recovery, allowing the metal concentration in the leachate 37to build up will improve metals recovery and reduce acid loses duringmetals recovery. A bleed stream 60 is taken from leachate stream 37 anddelivered to mixer 62 where the pH of the solution is adjusted to 1.5 to2.5 with lime or soda ash 61 before hydrogen sulphide gas 63 is appliedto the hot solution 66 in mixer 64. Base metal and other metal sulphides65 are precipitated and filtered. The filtrate 67 is heated to boilingand the pH is adjusted to between 3 to 3.5 with soda ash 68 in mixer 60resulting in the precipitation of iron as a compact iron oxide 70. Afterfiltering, the clear solution 71 is delivered to the vanadium recoverysection 73 where the vanadium ions are oxidised to their highest valencyof 5+by adding oxidising agents such as hydrogen peroxide 72. Afteradjusting the pH of the solution with soda ash or ammonia 74 to about3.6 to 4.6, hydrogen sulphide 75 is applied to the solution where someof the vanadium precipitates as sulphides 76. After filtration, the pHis further adjusted to between 8 to 10 with soda ash or ammonia causingthe rest of the vanadium to precipitate as an oxide 76. Vacuum 77 isapplied to the waste solution to recover hydrogen sulphide gas beforethe waste solution 78 containing mainly calcium, sodium and someammonium sulphate is delivered to the waste pond.

FIG. 4 is an embodiment of this invention where the heavy metals andsome sulfur is removed by acid leaching and electro-leaching and furtherremoval is carried out by an alkali leach of the acid leached crude oil.The acid leaching and washing is similar to FIG. 3 except that insteadof adding an oxidising agent 39 during leaching, the leach solution 37is passed through the anode cells 79 of an electrolyte system of thetype disclosed in Applicants U.S. Pat. Nos. 5,569,370 and 5,882,502 andAustralian patents 654774 and 707701, oxidising ions such as iron andvanadium allowing these ions to participate in the leaching process.Another acid solution could be circulated though the cathode cells 80 ofthe electrolytic system to produce hydrogen gas for use in the processof this invention. The washed acid leached crude oil is delivered tomixer 84 where the emulsifiers 82, if required and water 83 are added.The mixture is leached in leach vessel 85 using conventional heating andthen passed to the liquid liquid separator 86 where the leachate 87 issubjected to evaporation 101 to separate the caustic soda 102 forrecycle and the sulfur salts 103 which are delivered to the waste pond.The partially leached crude oil is then leached in vessel 89 withcaustic soda 88 with application of microwave energy. The leachate isthen removed in a double stage liquid liquid separation 90, 91 with theremoved leachate 92 being recycled to the first alkali leach vessel 85.Subsequently the crude oil is passed to a two stage washing system inmixers 93, 97 with washing water added at 96 and intermediate drying at94 and final double stage liquid liquid separation 98, 99 with the washwater 100 being recycled and the leached crude oil product 104 beingdelivered to storage, a pipeline or for refining as required.

The metals recovery is similar to the process shown and described inFIG. 3 after a blend stream 60 is taken from the leach liquor stream 81.

FIG. 5 is another example of the application of this invention where themetals and sulfur are leached with acid and electro-leaching beforemicrowave hydro-desulfurization. The illustration is similar to FIG. 3except the oxidising power of the anode cells is used to oxidise ions inthe leach liquor such as iron and vanadium to their higher valency stateso that these ions will participate in the leaching process. Leachliquor 37 is passed through the anode cells before a bleed stream 60 istaken from oxidised leached liquor 81. This embodiment of our inventionwill result in lower acid consumption and higher leach efficiency forsome crude oils.

FIG. 6 is an application of our invention using solvent extraction inthe recovery of the metals. FIG. 6 shows a 2-stage de-salting operationusing liquid vortex separations but this operation normally can beeliminated as the acid leaching will perform the de-salting function.

The crude feedstock 105 is mixed with the second stage wash 112 in mixer106. The mixture is fed into a vortex separator 107 for liquid liquidseparation where the salty water 133 with some solids is sent to thewaste pond and the crude oil is delivered to the first wash mixer 109where water 108 is added. The mixture from mixer 109 is subjected to twostages of liquid liquid separation 110 and 111 before the de-saltedcrude oil 113 is processed in the acid leach and washing section 114 andthen to the alkali leaching and washing section 122 before the washedoil 132 is passed to the heater 123 for subsequent refining indistillation column 136 for instance.

The acid leach liquor 115 or a bleed stream is processed in the solventextraction process 116 where metal ions are transferred to the stripsolution 134. Because metals can be plated out from the solution 134 bythe cathode cells 124 or alternatively precipitated by applying hydrogensulphide. The pH of the solution from the cathode cells 124 is adjustedand oxidised with oxidising agent 126 in mixer 127 before hydrogensulphide 128 is applied in mixer 129 to precipitate the vanadiumcompounds 130. Vacuum 131 is applied before solution 135 is returned forstripping duty in the solvent extraction process. Stream 117 is oxidisedin anode cells 119 and make-up acid 120 added before the leach solution121 is recycled to the acid leaching circuit. Iron is not removed in thesolvent extraction process and a bleed stream 118 is removed from stream117 for neutralisation and recovery of the iron.

A simple leaching apparatus is shown on FIG. 7A. The leaching apparatushas a horizontal cylinder 139 with means to apply conventional heating138 in a first few stages of the vessel and means to apply microwaveenergy 140 into the cylinder towards the latter part of the vessel withthe microwave energy 140 being fed through an external quartz window 141at the point of greatest turbulence. Intense turbulence and shearing ofthe leach mixture is achieved by a series of agitators 137 eachconsisting of an impeller with vertical fingers at the edge of acircular plate acting against closely located stabilisers 141. Bafflesseparate each agitation compartment to minimise short-circuiting of themixture.

A pipe method of microwave application is shown on FIG. 7B. Leachsolution and crude oil is circulated from a heated leach vessel 142 bypump 143 to several pipe microwave units 144. Each pipe microwave unit144 has a microwave magnetron 145 to supply microwave energy to theliquid mixture in the pipe. The end of each of the pipes 144 is inclinedat 45 degrees to reflect the microwaves into the mixture of crude andleach solution and prevent bouncing back to the magnetron. Aftertreatment with microwave energy some material is recycled 146 and someis transferred to the next stage 147.

The apparatus shown in FIGS. 8A, 8B, and 8C are suitable for highcapacity leaching as well as for hydro-desulfurisation which require adifferent method of applying the microwave to the mixture. The featuresof FIGS. 8A, 8B, and 8C can also be applied to a large compartmentalisedhorizontal cylindrical apparatus as in FIG. 7A.

When the apparatus shown in FIGS. 8A, 8B and 8C is used for leaching theapparatus includes an impeller shelf 148 which is solid and which drivesintermediate impeller 149 along the shaft and an impeller 151 at thebottom of the shaft. Baffles 150 near each intermediate impeller assistwith the intense mixing of crude oil and leach solution thereby givingvery good contact and very intense agitation and shearing of the liquidmixture is achieved by the bottom impeller 151 against the stabilisers152. General circulation of the mixture in the leach vessel is achievedby the aid of the stand-pipe 157, the intermediate impellers 149, andthe holes 158 on the circular plate of the bottom impeller.

The supply of microwaves to the vessel 155 in FIG. 8A is by means of aseries of magnetrons 156 and wave guides 153 extending into the vessel155. The microwaves are distributed along the wave guide by means ofseveral slotted wave guides 153 where the slots 154 include quartz,ceramic or Teflon covers. The slots 154 for dispersing the microwavesare closer at the bottom and further apart towards the top of theapparatus. A large amount of microwave energy can be applied to thecharge by this method rather than using the window method as shown inFIG. 7A.

In FIG. 8B is an alternative embodiment of reaction vessel for leachingor hydro-desulfurizing. In this embodiment the microwave feeding methoduses a short wave guide 160 above the magnetron 156 and a convectiontube 161 above each wave guide. The wave guide has a window 162 ofceramic, quartz or plastics material through which the microwave energyis released. This method concentrates the microwaves into the mostintense turbulent area of the apparatus.

In FIG. 8C an alternative method of supply of microwave energy is shown.In this embodiment the magnetrons 156 each have a shielded cableconductor 163 in the form of an antenna extending from the magnetron 156below the reaction vessel into the bottom of the convection tubes 161with a microwave window at the top of the antenna 164.

When used for leaching as discussed above the apparatus shown in FIGS.8A, 8B and 8C do not require a hollow shaft, however, when the sameapparatus is used in the hydro-desulfurisation process the shaft 148 canbe hollow so that hydrogen gas 159 can be supplied down the hollow shaftto be mixed intimately with the crude oil by the bottom impeller in theregion that the microwaves are applied. By this means maximum contact ofhydrogen gas with crude oil is achieved.

EXPERIMENTAL RESULTS Leaching

Microwave leaching tests were carried out using a 3-liter autoclavefitted with a 1.2 kw microwave generator at 2450 megahertz frequencywhere the microwaves are inserted into the autoclave through a quartzwindow at the bottom of the autoclave. The samples tested are a veryfluid reduced crude from the Middle East with a specific gravity of0.8418 at 36 C and a commercially available emulsified bitumencontaining 40 to 45 percent water which had a specific gravity of 0.9851at 28 C and an unknown uncut bitumen.

Leaching tests were carried out with an over-pressure of 8 bars ofnitrogen with sulfuric acid of 30% strength at 7.5% by volume. Thesamples absorbed microwaves readily during the test which range intemperature from 80 to 140 degrees Celsius. Higher temperatures resultedin the sulfuric acid reacting with the oil. The best extractionsobtained based on the analysis of the feed and the leached crude were:

Sulfur Vanadium Nickel Iron Crude 86.44 86.44 94.58 97.29 Emulsified50.00 75.00 77.78 60.00 Bitumen

We anticipate higher extraction rates than reported above because thelow rpm centrifuge used in the above tests was not efficient inseparating the leachate from the crude oil. Tests on the uncut bitumenwere discarded because high temperatures (greater than 165 C) were usedwhich resulted in the acid reacting with the bitumen.

The results indicated that the removal of sulfur and heavy metals ismuch easier for lighter crude but more difficult for heavy crude. Theaddition of small amounts of an oxidising agent such as hydrogenperoxide is expected to increase the extraction of vanadium based ontests in applicant's laboratory on recovering vanadium from a complexiron ore.

1. A process to extract and recover heavy metals and sulfur from crudeoil or petroleum fuel products comprising: emulsifying the crude oilwith an emulsifying agent; adding a leach solution containing aninorganic acid or alkali to the emulsified crude oil and leaching theemulsified crude oil at an elevated temperature and pressure to providea leached emulsified crude oil and a leachate; separating the leachedemulsified crude oil and the leachate; removing a proportion of theleachate; recovering sulfur or heavy metals from the leachate; washingthe leached emulsified crude oil with water; and separating the leachedemulsified crude oil and the washing water wherein the leaching step iscarried out during the application of microwave energy.
 2. A process toextract and recover heavy metals and sulfur from crude oil or petroleumfuel products comprising: emulsifying the crude oil with an emulsifyingagent; adding a leach solution containing an inorganic acid to theemulsified crude oil and leaching the emulsified crude oil at anelevated temperature and pressure to provide a leached emulsified crudeoil and a leachate; separating the leached emulsified crude oil and theleachate; removing a proportion of the leachate; recovering sulfur orheavy metals from the leachate; washing the leached emulsified crude oilwith water; separating the leached emulsified crude oil and the washingwater; and further leaching the acid leached and washed crude oil orpetroleum product with an alkali solution while being irradiated withmicrowaves to remove sulfur from the crude oil.
 3. A process to extractand recover heavy metals and sulfur from crude oil or petroleum fuelproducts comprising: emulsifying the crude oil with an emulsifyingagent; adding a leach solution containing an inorganic acid or alkali tothe emulsified crude oil and leaching the emulsified crude oil at anelevated temperature and pressure to provide a leached emulsified crudeoil and a leachate; separating the leached emulsified crude oil and theleachate; removing a proportion of the leachate; recovering sulfur orheavy metals from the leachate; washing the leached emulsified crude oilwith water; separating the leached emulsified crude oil and the washingwater; and microwave hydro-desulfurizing the leached and washed crudeoil using hydrogen gas at a temperature below about 220° C. to ensurethere is no quality degradation in the crude oil to produce adesulfurized crude oil and a hydrogen sulfide by-product; and recoveringsulfur from the hydrogen sulfide by-product.
 4. The process of claim 1,wherein viscosity of the crude oil is reduced by addition of a solventbefore the emulsifying step and the solvent is recovered for reuse bydistillation before the leaching step.
 5. The process of claim 4,wherein up to 20% by volume of the solvent is added to the crude oilbefore the emulsifying step.
 6. The process of claim 1, where up to 0.5%by weight of emulsifying agents is mixed with the crude oil or petroleumproduct before the leaching step.
 7. The process of claim 1, wherein theleaching step is carried out at temperatures of between about 25° C. to160° C. and pressure up to about 100 bars.
 8. The process of claim 1,wherein the leaching step is carried out during the application ofconventional heat.
 9. A process to extract and recover heavy metals andsulfur from crude oil petroleum fuel products comprising: emulsifyingthe crude oil with an emulsifying agent; adding a leach solutioncontaining an inorganic acid or alkali to the emulsified crude oil andleaching the emulsified crude oil at an elevated temperature andpressure to provide a leached emulsified crude oil and a leachate;separating the leached emulsified crude oil and the leachate; removing aproportion of the leachate; recovering sulfur or heavy metals from theleachate; washing the leached emulsified crude oil with water;separating the leached emulsified crude oil and the washing water; andwherein the leaching step is carried out during the application of bothconventional heat and microwave energy.
 10. The process of claim 1,wherein the leaching step comprises one or more stages with aliquid-liquid separation between stages and wherein the leaching step isconducted in a counter-current mode.
 11. The process of claim 1, furtherincluding one or more stages of liquid-liquid separation between theleaching step and the washing step.
 12. The process of claim 1, furtherincluding one or more stages of liquid-liquid separation between thecrude oil and a rich leachate.
 13. The process of claim 1, wherein thewashing step comprises one or more stages with a liquid-liquidseparation between stages and wherein the washing step is conducted tocounter-current mode.
 14. The process of claim 3, further including oneor more stages of liquid-liquid separation between the washing step andthe microwave hydro-desulfurizing step.
 15. The process of claim 2,wherein the alkali leaching step is carried out during the applicationof both conventional heat and microwave energy.
 16. The process of claim1, wherein the microwave energy is applied to the leach solution atabout 800 to 22,000 megahertz frequency.
 17. A process to extract andrecover heavy metals and sulfur from crude oil petroleum fuel productscomprising: emulsifying the crude oil with an emulsifying agent; addinga leach solution containing an inorganic acid to the emulsified crudeoil and leaching the emulsified crude oil at an elevated temperature andpressure to provide a leached emulsified crude oil and a leachate;separating the leached emulsified crude oil and the leachate; removing aproportion of the leachate; recovering sulfur or heavy metals from theleachate; washing the leached emulsified crude oil with water;separating the leached emulsified crude oil and the washing water; andwherein the leach solution contains an inorganic acid and includes asmall amount of an oxidizing agent including hydrogen peroxide.
 18. Aprocess to extract and recover heavy metals and sulfur from crude oil orpetroleum fuel products comprising: emulsifying the crude oil with anemulsifying agent; adding a leach solution containing an inorganic acidor alkali to the emulsified crude oil and leaching the emulsified crudeoil at an elevated temperature and pressure to provide a leachedemulsified crude oil and a leachate; separating the leached emulsifiedcrude oil and the leachate; removing a proportion of the leachate;recovering sulfur or heavy metals from the leachate; washing the leachedemulsified crude oil with water; separating the leached emulsified crudeoil and the washing water; and wherein the leaching step includesplacing anode cells in contact with the leachate to oxidize ionsincluding ferrous and vanadium ions before the leachate is recycled. 19.A process to extract and recovery heavy metals and sulfur from crude oilor petroleum fuel products comprising: emulsifying the crude oil with anemulsifying agent; adding a leach solution containing an inorganic acidor alkali to the emulsified crude oil and leaching the emulsified crudeoil at an elevated temperature and pressure to provide a leachedemulsified crude oil and a leachate; separating the leached emulsifiedcrude oil and the leachate; removing a proportion of the leachate;recovering sulfur or heavy metals from the leachate; washing the leachedemulsified crude oil with water; separating the leached emulsified crudeoil and the washing water; wherein the recovering sulfur or heavy metalsstep includes separating a bleed solution from a main leaching streamafter an anode cell; adjusting the pH of the bleed solution to aboutbetween 1.5 and 2.5 using calcium or sodium hydroxide or carbonate;applying hydrogen sulfide gas to the solution to precipitate metals andfiltering the precipitate; adjusting the pH of the boiling solution toabout between 3.0 to 3.5 using soda ash to precipitate iron oxide andfiltering the iron oxide precipitate from the solution; applying anoxidizing agent including hydrogen peroxide to convert vanadium ions totheir highest oxidation state before applying soda ash or ammonia to thesolution to increase the pH to about 3.6 to 4.6; applying hydrogensulfide gas to the solution to precipitate vanadium sulfide andfiltering the vanadium sulfide precipitate; adjusting the pH of the hotsolution to between about 8 and 10 using soda ash or ammonia toprecipitate vanadium hydroxide; and subjecting the waste solution to avacuum to recover any remaining hydrogen sulfide gas.
 20. The process ofclaim 3, wherein the hydro-desulfurizing step is carried out withcatalysts including cobalt or molybdenum on alumina.
 21. The process ofclaim 3, wherein the hydro-desulfurizing waste product of hydrogensulfide is processed in a conventional Claus or Stretford process toconvert the hydrogen sulfide into elemental sulfur and hydrogen gaswhich is re-cycled to the microwave hydro-desulfurizing step.
 22. Theprocess of claim 3, wherein the microwave hydro-desulfurizing step iscarried out in a high pressure and high temperature apparatus, theapparatus being provided with a supply of both conventional heating andmicrowave energy, fitted with a hollow shaft for the introduction ofhydrogen gas, and an impeller and baffle assembly to break-up the crudeoil into fine particles to provide intense mixing with the hydrogen gasand exposure to the microwave energy.
 23. The process of claim 1,wherein the emulsifying agents are applied in amounts up to about 0.5%by weight of the crude oil, the agents being sufficiently stable in acidand alkali conditions and temperatures below 160° C.
 24. The process ofclaim 1, wherein the leach solution is a solution of an inorganic acidor alkali which is about 5 percent to 50 percent by volume of the crudeoil.
 25. The process of claim 1, wherein the leaching is carried out ina vertical cylinder or a multi-compartment horizontal cylindrical vesseldesigned to function in the pressure, temperature, and corrosive natureof the crude oil leaching solution mixture.
 26. The process of claim 1,wherein the leaching is carried out in a leaching vessel provided with astand pipe and an agitation mechanism comprising an impeller and baffleassembly sufficient to circulate the mixture of crude oil-leach solutionand provide intense agitation and mixing in the area where microwaveenergy is being applied.
 27. The process of claim 1, wherein theleaching vessel is provided with external insulation and internal orexternal heating.
 28. The process of claim 1, wherein the wash watercontains alkali to ensure that the leached and washed crude oil has thebest quality for subsequent microwave hydro-desulfurizing.
 29. Theprocess of claim 3, wherein conventional heating is used to raise thetemperature of the crude oil between the washing step and thehydro-desulfurizing step.
 30. The process of claim 3, wherein themicrowave hydro-desulfurizing step is carried out at temperature of upto about 220° C.
 31. The process of claim 3, wherein the microwavehydro-desulfurizing step is carried out in the presence of a catalystincluding cobalt or molybdenum on alumina.
 32. The process of claim 3,wherein the microwave hydro-desulfurizing step is carried out in avessel comprising a vertical cylindrical vessel or a multi-compartmenthorizontal cylindrical vessel fitted with a standpipe and a hollow shaftfor the admission of hydrogen and an impeller-baffle assembly tointensely and intimately mix the leached crude and the hydrogen gas atthe space where the microwave energy is applied.
 33. The process ofclaim 32, wherein the microwave hydro-desulfurizing vessel is providedwith external insulation and internal or external housing.
 34. Theprocess of claim 32, wherein the microwave energy applied to themicrowave hydro-desulfurizing vessel ranges between about 800 and 22,000megahertz.
 35. The process of claim 32, wherein the microwavehydro-desulfurizing vessel is fitted with microwave generators and waveguides through quartz windows at the bottom or sides of the microwavehydro-desulfurizing vessel.
 36. The process of claim 3, wherein themicrowave energy for the hydro-desulfurizing step is applied in a seriesof pipes where the crude oil is being circulated from a holding vessel.37. The process of claim 3, wherein the microwave energy for thehydro-desulfurizing step is applied to the crude oil through wave guidesinside the vessel and wherein the microwave energy is delivered to thecrude oil through slots in the wave guides.
 38. The process of claim 3,wherein the microwave energy for the hydro-desulfurizing step isdelivered at the end of several short wave guides inside the vesselunder convection tubes at a space where there is maximum intense andintimate mixing of the crude oil and hydrogen gas.
 39. The process ofclaim 3, wherein the microwave energy for the hydro-desulfurizing stepis delivered at the end of antennae inside the vessel under convectiontubes at a space where there is maximum intense and intimate mixing ofthe crude oil and hydrogen gas.
 40. The process of claim 1, wherein ableed stream from a main leaching stream is separated continuously andfed to the recovering step.
 41. The process of claim 18, wherein a bleedstream from a main leaching stream is separated continuously and fed tothe recovering step wherein the bleed stream is separated after theanode cells.
 42. The process of claim 40, wherein the pH of the bleedstream is adjusted to between about 1.5 to 2.5 using calcium or sodiumhydroxide or carbonates.
 43. The process of claim 42, wherein hydrogensulfide is applied under pressure to the pH-adjusted bleed stream toprecipitate base and precious metals.
 44. The process of claim 43,wherein the metal sulfide precipitate is separated from the bleed streamby settling and filtration.
 45. The process of claim 44, wherein thebleed stream is brought to boiling and is pH-adjusted to between about3.0 to 3.5 using soda ash to precipitate the iron as a compact ironoxide which is then separated by filtration.
 46. The process of claim45, wherein the solution is treated with an oxidizing agent includinghydrogen peroxide to convert the vanadium to its highest valence of +5before adjusting the pH of the hot solution to between about 3.6 and 4.6using soda ash or ammonia.
 47. The process of claim 46, wherein thesolution is subjected to hydrogen sulfide under pressure to precipitatevanadium sulfide, the vanadium sulfide being separated by settling andfiltration.
 48. The process of claim 47, wherein the pH of the solutionis adjusted to between about 8 and 10 using soda ash or ammonia toprecipitate the remaining vanadium and to provide a clear solution. 49.The process of claim 48, where the clear solution is subjected to vacuumto recover hydrogen sulfide gas before discarding the solution.
 50. Theprocess of claim 3, wherein the microwave hydro-desulfurizing step iscarried out before the emulsifying and leaching steps.
 51. A process toextract and recover heavy metals and sulfur from crude oil or petroleumfuel products comprising making the crude oil readily broken down intovery small particles by applying solvents and emulsifiers to facilitatean intimate contact between the crude oil and a leaching solution duringleaching, providing an apparatus designed to withstand corrosiveconditions, temperatures of up to 160° C. and pressures up to 100 barsand fitted with a standpipe, impeller, and baffles to break-up the crudeoil into very small particles and intimately mix the crude oil particlesand the leaching solution, and utilizing the apparatus to apply heat andmicrowaves at about 800 to 22,000 megahertz frequency to the crudeoil-leach solution mixture to achieve the desired reaction temperature,wherein the leaching comprises one or more stages with a liquid-liquidseparator between stages arranged in counter-current mode, the leachsolution contains an inorganic acid or alkali or an oxidizing agentincluding hydrogen peroxide, a washing step that contains one or morewashing stages with liquid-liquid separators between stages arranged incounter-current mode where the wash water is supplied with alkali toensure the leached and washed crude oil is ideal feed for microwavehydro-treating or refining, and the leached and washed crude oil, if itcontains sulfur above a desired level, is subjected to microwavehydro-treating using hydrogen gas and conventional heating and microwaveactivation, and the hydro-treating is carried out at high pressure andat a temperature below 220° C.
 52. The process of claim 51, wherein theleaching step includes placing anode cells in contact with the solutionmixture to oxidize ions including ferrous and vanadium ions before theleach solution is recycled to the leaching step.
 53. The process ofclaim 51, further including a metals recovery step which comprises:separating a bleed stream from the solution mixture stream after ananode cell, adjusting the pH of the bleed solution to about between 1.5and 2.5 using calcium or sodium hydroxide or carbonate, applyinghydrogen sulfide gas to the solution mixture to precipitate metal sandfiltering the precipitate, adjusting the pH of the boiling solution toabout between 3.0 to 3.5 using soda ash to precipitate iron oxide andfiltering the iron oxide precipitate from the solution, applying anoxidizing agent including hydrogen peroxide to convert vanadium ions totheir highest oxidation state before applying soda ash or ammonia to thesolution to increase the pH to about 3.6 to 4.6, applying hydrogensulfide gas to the solution to precipitate vanadium sulfide andfiltering the vanadium sulfide precipitate, adjusting the pH of the hotsolution to between about 8 and 10 using soda ash or ammonia toprecipitate vanadium hydroxide, and subjecting the waste solution to avacuum to recover any remaining hydrogen sulfide gas.
 54. A process toextract and recover heavy metals and sulfur from crude oil or petroleumfuel products comprising: emulsifying the crude oil with an emulsifyingagent; adding a leach solution containing an inorganic acid to theemulsified crude oil and leaching the emulsified crude oil at anelevated temperature and pressure to provide a leached emulsified crudeoil and a leachate; separating the leached emulsified crude oil and theleachate; removing a proportion of the leachate; recovering sulfur orheavy metals from the leachate; washing the leached emulsified crude oilwith water; and separating the leached emulsified crude oil and thewashing water; wherein the leaching step comprises: leaching theemulsified crude oil with an acid leach solution, washing the acidleached emulsified crude oil with water, separating the crude oil fromthe wash water, re-emulsifying the crude oil, leaching the re-emulsifiedcrude oil with an alkali leach solution, washing the alkali leachedre-emulsified crude oil with water, and separating the crude oil fromthe wash water.
 55. The process of claim 54, wherein the acid and alkalileached crude oil is subsequently microwave hydro-desulfurized.
 56. Theprocess of claim 9, wherein the microwave energy is applied to the leachsolution at about 800 to 22,000 megahertz frequency.
 57. A system toextract and recover heavy metals and sulfur from crude oil or petroleumfuel products comprising: a mixer adapted to receive the crude oil orpetroleum fuel products and an emulsifying agent to provide anemulsified product; a leaching device which combines the emulsifiedproduct and a leaching solution to form a leached emulsified product anda leachate during the application of microwave energy; a microwavegenerator to provide microwave energy to the leaching device; a firstseparator, said first separator providing a leached emulsified productstream and a leachate stream; and a recovery system to treat theleachate stream, said recovery system constructed to recover sulfur orheavy metals.
 58. The system of claim 57, wherein said first separatorcomprises two or more stages having liquid-liquid separators disposedbetween said two or more stages.
 59. A system to extract and recoverheavy metals and sulfur from crude oil or petroleum fuel productscomprising: a mixer adapted to receive the crude oil or petroleum fuelproducts and an emulsifying agent to provide an emulsified product; aleaching device for combining the emulsified product and a leachingsolution to form a leached emulsified product and a leachate; a firstseparator, said first separator providing at leached emulsified productstream and a leachate stream; a recovery system to treat the leachatestream, said recovery system constructed to recover sulfur or heavymetals; a microwave hydro-desulfurization device disposed downstream ofthe first separator, said microwave hydro-desulfurization device adaptedto generate a desulfurized crude oil and a hydrogen sulfide by-product;a second separator, said second separator providing a desulfurized crudeoil stream and a hydrogen sulfide by-product stream; and a sulfurrecovery device to recover sulfur from the hydrogen sulfide by-productstream.
 60. The system of claim 59, wherein said second separatorcomprises two or more stages having liquid-liquid separators disposedbetween said two or more stages.
 61. The system of claim 59, furthercomprising a washing device disposed downstream of said microwavehydro-desulfurization device, and a third separator providing a washed,desulfurized crude oil stream, wherein said third separator comprisesone or more stages having liquid-liquid separators disposed between saidtwo or more stages.
 62. The system of claim 59, wherein said microwavehydro-desulfurization device further comprises conventional heaters. 63.The system of claim 59, wherein said microwave hydro-desulfurizationdevice is fitted with a hollow shaft for the introduction of gas, and animpeller and baffle assembly to provide intense mixing.
 64. The systemof claim 59, wherein said microwave hydro-desulfurization device is avertical cylindrical vessel.
 65. The system of claim 59, wherein saidmicrowave hydro-desulfurization device is a multi-compartment horizontalcylindrical vessel.
 66. The system of claim 59, wherein said microwavehydro-desulfurization device is fitted with microwave generators andwave guides through quartz windows disposed at the bottom or sides ofsaid microwave hydro-desulfurization device.
 67. A system to extract andrecover heavy metals and sulfur from crude oil or petroleum fuelproducts comprising: a mixer adapted to receive the crude oil orpetroleum fuel products and an emulsifying agent to provide anemulsified product; a leaching device for combining the emulsifiedproduct and a leaching solution to form a leached emulsified product anda leachate; a first separator, said first separator providing a leachedemulsified product stream and a leachate stream; and a recovery systemto treat the leachate stream, said recovery system constructed torecover sulfur or heavy metals; wherein said sulfur or heavy metalsrecovering system further comprises: a conveyance device in fluidcommunication with the leaching device and a first mixer said firstmixer adapted to permit adjustment of the pH of the leachate to about1.5 to 2.5 using calcium or sodium hydroxide or carbonate; a secondmixer adapted to introduce hydrogen sulfide gas to the pH-adjustedleached product, said second mixer disposed downstream of said firstmixer and constructed to permit removal of precipitated sulfides from asulfide-lean product stream; a third mixer disposed downstream of saidsecond mixer, said third mixer adapted to heat and adjust the pH of thesulfide-lean product stream to about between 3.0 and 3.5 and constructedto permit removal of iron as a precipitate; a vanadium recovery systemdisposed downstream of said third mixer, said vanadium recovery systemadapted to introduce an oxidizing agent and to permit pH-adjustment toincrease the pH to about 3.6 to 4.6 to recover precipitated vanadiumsulfides and vanadium oxide; and a vacuum device to recover waste gasesdownstream of said vanadium recovery system.